Hi there-- I think you have some good choices here, but here are some suggestions:

  1. Replace the 1u effects module with something like Erica Synths Pico DSP.
  2. Replace the current VCA with the Intellijel 1u dual VCA.
  3. Add in a 1u Sloths from Nonlinearcircuits. It's a fantastic modulation source, and it's tiny and cheap.
  4. Replace the MI attenuator/mixer with a 1u version. Transient Modules makes one that is 1u and Intellijel format.
  5. There are tons of ring modulators out there in 3 or 4 hp... so I'd replace the Pittsburgh module with a smaller version.
  6. If you make those swaps, you should still have somewhere between 4-7 hp left to play with. Use that space to add a Disting. It just barely fits into the Palette case, and it basically does whatever you need it to do.... extra VCO, ring modulator, filter, reverb, LFO, etc. etc.